<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<meta name="viewport" content="width=device-width, initial-scale=1">
		<title></title>
		<!-- 
		  BOM(browser object model) 浏览器对象模型
		
		  window全局对象(浏览器窗口)
	    -->
	</head>
	<body>
		
	</body>
</html>